/*编写一个程序,读取键盘输入,知道遇到@符号为止
 * 并回显输入(数字除外),同时将大写字符转化为小写
 * 将小写字符转化为大写(别忘了cctype函数系列);
*/
#include<iostream>
#include<cctype>
int main()
{
    using namespace std;
    char ch;
    cout << "Please Enter a character to next step."<< endl;

    cin.get(ch);
    while (ch != '@')
    {
        if(isdigit(ch))
            cout<< "";
        else if(isupper(ch))
            cout << char(tolower(ch));      //如果是大写则转化为小写同时将参数转化为小写字符格式
        else if(islower(ch))
            cout << char(toupper(ch));
        cin.get(ch);
    }
    return 0;

}
